Telematics units enable a service provider to remotely connect to the telematics unit without a service subscriber being in the vehicle in order to provide services, such as a door unlock service. To determine the telematics unit identification number, the state of the telematics unit and the location of the vehicle, service providers rely on verbal information provided by a subscriber, such as that they are not in the vehicle and the keys are locked inside.
To conserve battery power a sleep cycle is used where the telematics unit cycles between a powered on and powered off state for a period of time. The service provider does not have the ability to determine the current state of the telematics unit, without issuing a request and waiting for a response. If a service is requested by a subscriber, the service provider transmits the service to the telematics unit and waits for the telematics unit to acknowledge the service. For example, if a door unlock service is requested, the service provider does not know whether the telematics unit is on or off and therefore cannot supply the subscriber with an exact time that the door will unlock.
In addition, location information is not readily discernable by the service provider thereby limiting the ability of the service provider to supply location based services. Location based services include weather alerts, traffic reports and vehicle tracking.
Various protocols can be used for communication between the service provider and the telematics unit. One such protocol is the session initiation protocol (SIP). SIP is a text-based peer-to-peer protocol that facilitates the formation, modification, and execution of communication sessions between two or more participants also referred to as user agents. The user agent can be a personal computer, landline Internet-protocol telephony telephone system, an automation component such as a voicemail server, or a communication device such as a telematics unit. Interactions include peer-to-peer and multipoint communications.
Each user agent is identified by an address, referred to as the SIP uniform resource indicator or SIP URI that simulates an email address and is used for identification and location purposes. The SIP URI contains a userinfo field and a domain field. A user parameter is used to identify the userinfo field as a phone number or an IP address. This SIP URI specifies the user agent's address and location on the network but does not provide information relating to the geographic location of the SIP user agent, nor does it provide information relating to the availability of the user agent as indicated by the operational status of the SIP user agent. Without this information, the level of service that can be supplied by the service provider is limited.
A session initiation protocol (SIP) network is composed of five types of logical SIP entities including a user agent, a proxy server, a redirect server, a registrar server, a back-to-back user agent. Each entity has specific functions and participates in SIP communication as a client (initiates requests), as a server (responds to requests), or as both. The SIP specification is provided by the Internet Engineering Task Force (IETF) in RFC 3261 which is herein incorporated by reference in its entirety.
SIP has a limited library of requests. The library includes INVITE, REGISTER, BYE, INFO, OPTIONS, and MESSAGE.
It is therefore desirable to provide a method and system for providing telematics unit information that overcomes the limitations, challenges, and obstacles described above.